This invention relates to a method for producing structured, self-organizing molecular monolayers of individual molecular species. The invention is preferably applied in the formation of solid phase-coupled substance libraries or in other assays for testing molecular interactions. Libraries of this kind which are used for fast detection of interacting reactants in the molecular field are known, in principle. Such substance libraries are generated in different ways according to the known prior art nearest to the invention. Thus, it is known to use so-called xe2x80x9cmicrobeadsxe2x80x9d; i.e, small beads which are provided with a molecular reactant on their surface. Furthermore, a so-called xe2x80x9cmixandsplitxe2x80x9d procedure is known for producing such libraries (Erb, E.; Jander, K. D.; Brenner, S.: Recursive Deconvolution of Combinatorial Chemical Libraries, Proc. of Natl. Acad. Sci. USA 91, pg. 11422-6 (1994)). Solid phase-coupled libraries are particularly advantageous, the components of which are uniquely determined by their position (x-y-direction). For the serial production of such libraries modified jet printers are employed, for example, which by point-spraying apply the substances to be brought together on a preselected substrate (Schober, A. Guenther, R.; Schwienhorst, A. Doering, M.; Lindemann, B. F.: Accurate high-speed Liquid handling of very small biological samples, Biotechniques 15: pg. 324-9, 1993). So-called xe2x80x9capplicatorsxe2x80x9d have to be used for the parallel generation of such libraries, whereby a head being provided with a plurality of thin channels is set upon a surface, the head being adapted to simultaneously supply a plurality of micro-reaction cavities; refer, for example, to U.S. Pat. No. 5,429,807. Furthermore, to the same end, the application of light-activatable protective groups (U.S. Pat. No. 5,489,678) and of print-techniques has already been described (DE 195 43 232.0).
One or more basic disadvantage are inherent in these known methods and devices:
Thus the use of a jet-printer does not permit simultaneously supplying a greater number of surface elements with a substance all at once, since the process concerned is a serial one. The devices known as xe2x80x9capplicatorsxe2x80x9d are limited in to their technically feasibility with respect to the degree to which they can be miniaturized. The printing syntheses, which utilize prints having structurized and profiled surfaces for transferring substances, cause considerable problems with respect to an exact positioning; hence, reproducible multiple syntheses are practically excluded. Known methods of the complex protective group chemistry which use light-activatable protective groups require long exposure times when a high step efficiency is desired at, whereby the entire process for producing a library is rendered very time-consuming. Moreover, the light sensitivity of the last mentioned method necessitates a particularly expensive execution of the process. In Proc. Natl. Acad. Sci. USA, vol. 93, November 96, pg. 13555-13560 such a method for generating substance libraries is described in which at first a substrate is provided with a suitable protective group or with a monomer supporting a first protective group. Then a substrate surface is coated with a light-activatable photo-resist layer, and partial areas are exposed and structurized according to a preselected synthesis algorithm. In the structurized areas, the splitting-off of the protective group is carried out, then the bonding to a second polymer can be carried out in the exposed areas. After removal of the remaining photo-resist layers the entire process can be repeated with an accordingly adapted photo-resist layer which has to be structurized anew. The main disadvantage in this procedure is, apart from the disadvantages mentioned hereinbefore, the incomplete removal of the residues of the photo-resist layers from the library matrix, whereby the output per synthesis step and, hence, the entire synthesis output decreases.
It is an object of the present invention to provide a method for producing structured, self-organizing molecular monolayers of individual molecular species which permits the reproducible and multiple repeatability of the formation and locally defined bonding of molecular units to molecular monolayers, and ensures a high output. In particular, the method to is particularly intended for the production of test-assays and of solid-phase-bonded substance libraries.
According to the invention specially prepared micro-structurized polymeric masks are employed which are designed to be deposited upon a substrate and which, in preselected areas, are provided with apertures which permit the generation of monomolecular monolayers on the substrate.